[src/trunk]: src/sys/ddb ddb(9): Make db_symstr safe to use concurrently with...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6f24c6757020
branches:  trunk
changeset: 369770:6f24c6757020
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Tue Aug 30 22:38:01 2022 +0000

description:
ddb(9): Make db_symstr safe to use concurrently with pserialize(9).

diffstat:

 sys/ddb/db_sym.c |  13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diffs (57 lines):

diff -r d3cd2a2863b5 -r 6f24c6757020 sys/ddb/db_sym.c
--- a/sys/ddb/db_sym.c  Tue Aug 30 22:37:36 2022 +0000
+++ b/sys/ddb/db_sym.c  Tue Aug 30 22:38:01 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_sym.c,v 1.70 2022/08/30 22:37:36 riastradh Exp $    */
+/*     $NetBSD: db_sym.c,v 1.71 2022/08/30 22:38:01 riastradh Exp $    */
 
 /*
  * Mach Operating System
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_sym.c,v 1.70 2022/08/30 22:37:36 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_sym.c,v 1.71 2022/08/30 22:38:01 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddbparam.h"
@@ -37,6 +37,7 @@
 #include <sys/proc.h>
 #include <sys/systm.h>
 #include <sys/ksyms.h>
+#include <sys/pserialize.h>
 
 #include <ddb/ddb.h>
 
@@ -344,13 +345,14 @@
        }
 #endif
 #ifdef _KERNEL
+       const int s = pserialize_read_enter();
        if (ksyms_getname(&mod, &name, (vaddr_t)off,
            strategy|KSYMS_CLOSEST) == 0) {
                (void)ksyms_getval_unlocked(mod, name, NULL, &val, KSYMS_ANY);
                if (strategy & KSYMS_PROC && val == off) {
                        if (ksyms_getname(&mod, &name, (vaddr_t)off - 1,
                                          strategy|KSYMS_CLOSEST) != 0)
-                               goto out;
+                               goto hex_fallback;
                        (void)ksyms_getval_unlocked(mod, name, NULL, &val, KSYMS_ANY);
                }
                if (((off - val) < db_maxoff) && val) {
@@ -368,11 +370,12 @@
                                            " [%s:%d]", filename, linenum);
                        }
 #endif
-                       return;
+                       goto out;
                }
        }
-out:
+hex_fallback:
        db_num_to_strbuf(off, buf, buflen);
+out:   pserialize_read_exit(s);
 #endif
 }